Simple dynamic typing in Kotlin with Kotson

Apparently, it is possible to make Kotlin have a very simple dynamic typing, like JavaScript, with a JSON library -- Kotson, with some tweaks.

In JavaScript, there are only very few types, String, Number, Boolean, Null, Undefined, Object; and Array, which is a special kind of object.

With Kotson, Kotlin and

fun JsonObject.getValueOrNull(key: String): Any? {
    return if (contains(key)) {
        get(key).asValue()
    } else null
}

fun JsonArray.getValueOrNull(index: Int): Any? {
    return if (index >= 0 && index < size()) {
        get(index).asValue()
    } else null
}

fun JsonElement.asValue(): Any {
    return try {
        asDouble
    } catch (e: Exception) {
        try {
            val s = asString
            if (setOf("true", "false").contains(s)) {
                asBoolean
            } else s
        } catch (e: Exception) {
            this
        }
    }
}

Now, the typing is now limited a very few…

• String -- class java.lang.String
• Number -- class java.lang.Double
• Null -- class com.google.gson.JsonNull
• Boolean -- class java.lang.Boolean
• Array -- class com.google.gson.JsonArray
• Map -- class com.google.gson.JsonObject
• Undefined -- null

Very simple, isn't it? Also, the comparison is now simpler. For more of how I use it, see https://github.com/patarapolw/rep2recall-kt/blob/master/src/main/kotlin/rep2recall/json/JsonUtil.kt.